1. Field of the Invention
The present invention relates to a noncontact IC card interface unit for communication with a noncontact IC card.
2. Description of the Related Art
In recent years, noncontact IC cards have been developed and put to use. The advantages of the noncontact IC card lie in that (1) it is useful because it need not be loaded in a reader writer and is accessible at a remote place, and that (2) it is not prone to a malfunction due to imperfect contact or a failure due to static electricity, because it does not require any electrodes unlike any known contact IC card.
FIG. 23 is a schematic block diagram showing a communication system for data communication with a known noncontact IC card 1. As shown in FIG. 23, an interface unit 4 such as a reader/writer is electrically coupled with a host computer 2 by means of a serial able 3 such as one conformable to RS-232C. The interface unit 4 consists of a controller 4a that includes an MCU and that controls bidirectional data transfered between the noncontact IC card 1 and host computer 2 by generating a control signal for use in controlling internal elements of the interface unit 4 in response to a memory access signal sent from the host computer 2, a transmitter-/receiver 4b including a modulator/demodulator, and an antenna 4c for transmitting or receiving a transmission or reception signal 5 transferred to or from the noncontact IC card 1. The antenna 4c is not incorporated in the body of the interface unit 4 but is electrically connected with the transmitter/receiver 4b externally of the body. The transmitter/receiver 4b modulates transmission data sent from the controller 4a so as to produce a transmission signal to be sent to the noncontact IC card 1 via the antenna 4c, or demodulates a reception signal sent from the noncontact IC card 1 via the antenna 4c so as to convert it into digital data.
In the above communication system having the foregoing configuration, the interface nit 4 serves as a mere repeater for facilitating communication between the host computer 2 and noncontact IC card 1. The interface unit 4 does not retain data read from the noncontact IC card 1 via the antenna 4c but merely transfers the data consecutively to the host computer 2. Since the transmission rate of data transfer between the noncontact IC card 1 and antenna 4c is usually low (approximately 19.2 bps at highest), the transmission rate of data transfer between the host computer 2 and interface unit 4 need not be very high. The serial cable 3 is therefore used to connect the host computer 2 to the interface unit 4. This poses a problem in that the memory in the known noncontact IC card cannot be accessed (read or written) at a high speed unlike the one in a known contact IC card.
The employment of the known contact IC card guarantees quick access. When an attempt is made to acquire data from the IC card through another host computer, the IC card must be ejected from a currently-used host computer. At the time of inserting and ejecting an IC card, force is applied to a connector of the IC card. This results in mechanical damage or imperfect contact.